21001011212021 has 2 divisors, whose sum is σ = 21001011212022. Its totient is φ = 21001011212020.

The previous prime is 21001011211967. The next prime is 21001011212047. The reversal of 21001011212021 is 12021211010012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20872014588100 + 128996623921 = 4568590^2 + 359161^2 .

It is a cyclic number.

It is not a de Polignac number, because 21001011212021 - 2¹⁰ = 21001011210997 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21001011211987 and 21001011212005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001011212821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500505606010 + 10500505606011.

It is an arithmetic number, because the mean of its divisors is an integer number (10500505606011).

Almost surely, 2^{21001011212021} is an apocalyptic number.

It is an amenable number.

21001011212021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001011212021 is an equidigital number, since it uses as much as digits as its factorization.

21001011212021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21001011212021 its reverse (12021211010012), we get a palindrome (33022222222033).

The spelling of 21001011212021 in words is "twenty-one trillion, one billion, eleven million, two hundred twelve thousand, twenty-one".